Retinoscope.



Patented lan. 29, |90I. E. LE R. RYER.

R'ETINDSCUPE.

(Application lad Sept. 17, 1900.)

3 Sheets-Shed I.

(No Model.)

No. 666,656. Patentedlan. 29, |901.

E. LE R. RYER.

nE'TmoscoPE.

(Application ma sm. 17 1906. (no nodal.)

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ncitizen of the United States, and a resident of UNITED STATES ELMER LE ROY RYER,

or New YORK, N. Y.

'FiE'TlNosCoP'e SPECFICAT-ION forming part of Letters Patent No; 666,856, dated January 29, 1901. Application iiled September 17, 1900. serial No. 30,241. (No model.)

"0 all whom .ttm/ay concern:

Beit known that I, ELMER LE RoY RYER, a

NewYork city, in the county of New York and y State of New York, have invented certain new and useful Improvements in Retinoscopes, of which the following is a specification.

The invent-ion relates to improvements in retinoscopes; and it consists in the novel features and combinations of parts hereinafter described, and particularly pointedout in the claims.

The object of the invention is to provide an adequate and improved instrument by which the oculist, optician, retinoscopist, or other operator may examine and determine the condition of the human eye and tit proper lenses for correcting and improving the sight ot' the same.

The invention and satisfactory means for carrying the same into eifect will be fully understood from the detailed description hereinafter presented, reference being had to the accompanying drawings, in which- Figure 1 is a top view, partly in section and partly broken away, of a retinoscope constructed in accordance with and embodying the invention. Fig. 2 is a vertical transverse section of same on the dotted line 2 2 of Fig.v 1 and illustrates the slide carrying the spher. ical lenses in position. Fig. 3 is a detached bottom View of a portion of the instrument and illustrates more particularly the segment and worm-gearing provided for effecting the lateral pivotal movement of the interior 0bserving-tube ot' the instrument. Fig. 4 is a front elevation of the front end of the instrument, the light-chamber being omitted. Fig. 5 is a detached side elevation of a portion vof the slide which carries the cylindrical lenses. Fig. 6 is a vertical transverse section of same on the dotted line 6 6 of Fig. 5. Fig. 7 is a side elevation, partly broken away and partly in section, of the retinoscope embodying my invention, the light-chamber being omitted. Fig. 8 is an enlarged cen tral' vertical longitudinal section of the front portion of saule on the dotted line8 Bof Fig. 1. Fig. 9 is a horizontal longitudinal section, partly broken away, of the front portion of same on the dotted line 9 9ct Fig. 7. Fig. 10is a vertical transverse section of same on the dotted line 1010 of Fig. 7. Fig. 1l is a detached sidel elevation, looking at the left-hand side of the' instrument, of a portion of the gearing for operating the lens-slides. Fig. l2 is an end ele' vation of the prism through which the operator looks and which refracts or reiiects the lightintothe eyeofthepatient. Figlisatop view of same. Fig. 14 is an enlarged central vertical longitudinal section through the outer portion of the instrument on the dotted line 14 14 oi" Fig. 1. Fig. 15 is a horizontal longitudinal section through a portion of the gear ing for operating the chin-rest on the dotted line l5 15 of Fig. 14. Fig. 16 is an end view, partly broken away, of the casing which forms the light-chamber. Fig. 17 is a central vertical section of same on the dotted line 17 17 of Fig. 16; and Fig. 18 is a view substantially corresponding with Fig. 9, but showingastationary apertured mirror at the operators end of the observing-tube instead of a prism.

In the drawings, 25 denotes the main eX- terior casing of the instrument, which casing is shown as being oblong in cross-section and of trumpet shape, being larger at its outer or rear end than at its inner end and having gradually-diverging side Walls from the inner to the outer end. The casing 25 may be of wood or other material and is mounted upon 'a vertically-adj ustable support 26 in any suitable manner, the purpose of the adjustment `of the support 26 being to permit of the raising and lowering of the casing 25 to suit the varying conditions which may arise in the use of the instrument. The casing 25 at its outer end Will be provided with the shield 27 to inclose that portion of the face around the eyes of the patient, and at its inner end the instrument will be provided with the eyepieces 29 and 30 for the eyes of the operator, the eyepiece 29 having an aperture through which the operator may look, while the eyepiece 30 is simply a blank to shield that eye of the operator not engaged at the eyepiece 29. The shield 27 will preferably be of pliable material, such as soft sheet-lead, covered, if necessary, withatextile fabric, so that the said shield may be made to closely conform to the outline of the face of the patient, as shown in Fig. 14, thereby to exclude the exterior light from the eyes of the patient. The shield 27 is fixed to the outer end of the IOO casing 25 and is of suiiicient dimensions to inclose both eyes of the patient, it being highly desirable that the patient should at all times have both of his eyes centered Within the interior of the casing 25. The casing 25 is, in eiect, a broad dark chamber into which the patient will look, while the operator by means of the inner observing-tube 31 will direct the light into and across the eyes of the patient and at the same time look through said tube into said eyes. The inner walls of the casing 25 will be painted black or covered with black fabric.

The inner or observing tube 31 is formed by preference of telescopic sections, as shown, so that it may be lengthened or shortened at will for the purpose ot' bringing the outer end of the said tube nearer to or farther from the eyes of the patient. The nearer the inner end of the tube 31 is brought to the eye of the patient the smaller will be the beam of light thrown upon the said eye, and the farther the outer end of the tube 31 is removed from the eye of the patient the larger will be the reflection of light thrown upon said eye. I have illustrated the tube 31 in its extended position, and in this position it will meet all of the requirements incident to the examination of eyes in their usual conditions and not unduly sensitive. When the eyes are unduly sensitive, the tube 31 should be shortened. For convenience in adjusting the sections of the telescopic observing-tube 31 I provide a door 32 in one side of the casing 25 and secure to the outer section of the tube 31 a knob or handle When the door 32 is open, the operator may readily reach the handle 33 and by means of the latter adjust the outer section of the tube 31 at will.

The observing-tube 31 is pivotally mounted, so that the outer end of said tube may be moved from in line with one eye to the other of the patient, and the front portion of the said tube 31 is mounted upon a saddle 34, from which a horizontal arm 35 extends frontward, the latter being keyed upon the Vertical bolt 36, as shown in Fig. 8. Below the casing 25 is secured a plate 37, which extends frontward directly below the arm 35 and is free upon said bolt 36. The plate 37 carries the worm 38, as shown in Figs. 3 and 8, and upon the bolt 36 is secured the segment 39, the latter being in mesh with the said worm. A nut 40 upon the bolt 36 retains the segment 39 in position upon a square portion of the bolt 36. The worm 38 is provided with the outwardly-extending rod 41, having a handleA 42, the latter being for the use of the operator in the manual rotation of the worm 38. Vhen the worm 38 is rotated by the operator, it will move the segment 39 laterally and impart a partial rotatory motion to the bolt 36, which during such motion will impart a lateral Amovement to the arm 35 and saddle 34, the

bolt 36 serving as a pivotal center on which the arm 35 and saddle 34 will have their movement. The movement of the saddle 34 under the inliuence ot' the worm 38 and segment 39 has the effect of imparting a pivotal movement to the interior observing-tube 3l, the center of such movement of the tube 31 being at the bolt 36, which is below the front end of said tube 31, in consequence of which the front or operators end of the tube 31 will have a very slight movement during the passage of the outer end of the tube 31 from a position in line with one eye of the patient to a position in line with the other eye of the patient. That front portion of the observingtube 31 which is within the front end of the casing 25 is provided with the collars 43 44, adapted to slide within a frame 45 at the front end of the casing 25, and between the collars 43 and 44 are secu red the inner edges of a piece of loose black cloth or other fabric 46, whose outer edges are secured to the said frame 45. The purpose of the cloth 46 is to enable the observing-tube 31 to perform its pivotal movement without dangerof the exterior light entering t'ne front end of the casing 25 during such movement. That portion of the tube 31 within the casing 25 is simply a plain, empty, and dull-black-surfaced tube, preferably though not necessarily of telescopic character, and the sole purpose of the Worm 38 and segment 39, with their coperative parts, is simply to enable the operator to center the observing-tube 31 rst upon one eye and then upon the other eye of the patient.

At the inner or operators end of the observing-tube 31 is provided the chamber 47 to receive the prism 48, which contains the aperture 4f) in line with the aperture in the eyepiece 29 for the operator, as clearly shown in Figs. 8 and 9. The chamber 47 for the prism 48 is formed in the casting 50, which is secured to the end of the tube 31 by means ofthe half-sleeves 5l 52, secured together and upon the end of the tube 31 by means of screws 53. The half-sleeves 5l 52 have iingers 54, which extend forward above and below the casting 5() and. are provided with screws 55, as shown in Figs. 7 and 8, which may be screwed inward to press packingpieces 56 inward against pins 57, carried by the upper and lower plates 58, which are at the upper and lower sides of the casting 50, said plates 58 closing the upper and lower sides of the chamber 47, containing the prism 48. The plates 58 may be of any desired material. The casting 50 and plates 53 are placed together and upon the lower finger 54 of the half-sleeve 52, and the latter is placed against the lower side of the front end of the tube 31, and thereupon the upper half-sleeve 51 is placed upon the front end of the tube 31 to match with the lower half-sleeve 52, whereupon the screws 53 will be applied, and the securing of the latter will operate to draw the two half-sleeves 51 52 toward one another, so as to fasten said half-sleeves upon the tube 31 and cause the fingers 54 of the said halfsleevesto operate as a means for holding the casting 50 and its parts securely in position.

The plates 58 by the securing of the halfsleeves 51 52 will be firmly pressed against the casting 50, and the plates 58 will be secured against slidingoutward from the fingers 54 by means of the pins 57 and screws 55, the latter holding the pins 57 in rigid position. The Lipper and lower plates 58 and casting 50 may also be secured together by means of a screw 59. The casting 50 forms the chamber 47 and comprises the eyepieces 29 and 30, with the plate 60, which connects said eyepieces, and at one side of the casting 50 is the threaded sleeve 61 to receive the light-tube 62,upon which is placed the Wooden tube 63, at whose outer end the light-chamber casing 64 is connected by a short branch tube 65, as shown in Fig. 17. The invention is not limited to any special form of branch tube 62 and casting 50 nor to any special means for securing the casting 50 to the observing-tube 31, these being matters of detail which will vary according to the will of the manufacturer. The light-chamber casing 64 is cylindricalin vertical transverse section, as shown in Figs. 16 and 17, andthe main body 66 thereof is substantially rigid with the Wooden tube 63 and branch tube 65. It may be proper here to say that the wooden tube 63 is employed merely because of the fact that it will not become unduly heated from the light within the chamber 64. The main body 66 of the casing 64 is provided at its upper side with the outlet flue or chimney 67 and at its lower side is provided with the slot 68, while upon the outer end of the said casing 64 is provided the rotary cap 69, which lits upon the body 66 and is capable of being turned thereon by hand. The cap 69 is provided upon its outer face with the rack-plate 70, arranged between guides 71 and adapted to be operated by the pinion-wheel 72, which i's secured upon the cap 69 and provided with an operating wheel or handle 73. Behind the sliding rack the cap 69 is provided with an elongated slot 74, and through this slot 74 projects an arm 75, to which the sliding rack 70 is positively secured. The arm 75 supports the swinging bracket 76, which carries the burner 77, the latter being supplied with gas through a exible tube 78. The bracket 76 is provided with the weight 79, which keeps it and the burner 77 in a vertical position at all times, notwithstanding the rotary motion which may be given to the cap 69, carrying the sliding rack 70. The sliding rack 7() carries the arm 75 and swinging bracket 76, and this slide 70 is adapted to be moved back and forth by the operator through the medium of the handwheel 73 and pinion-wheel 72, the lat-rer directly meshing with the teeth of the slide 70. rIhe slot 68 in the body portion 66 of the lightchamber casing 64 is somewhat elongated, so as to permit of the bracket 76 remaining in a vertical position during the sliding motion of the slide 70, carrying said bracket 76, and also to permit the said bracket 76 remaining in a vertical position during the partial rotary motion which may be given to the cap 69. The present invention is not limited to any special means for creating artificial light Withinthe casing 64; but the burner 77 illustrated will afford a satisfactory means for utilizing acetylene gas for creating this light. The light within the light-chamber casing 64 will pass through the tubes 63 and 62 to the prism 48 and be by the latter refracted through the observing-tube 31 to the eye of the patient, and in order that the eye may be properly examined with regard to all its peculiarities of condition I provide that the bracket 76, supporting the burner, may be moved back and forth by means of the pinion-wheel 72 and also provide that the cap 69 may have a partial rotary motion upon the body 66 of the light-chamber casing 64, it being possible with such principle of construction to give the eye its proper and thorough examination Without moving the tube 62 in a rotary direction upon the end of the tube 31 and without being put to the necessity of employing a tilting or vibrating oscillatory mirror or retinoscope at the end of the observing-tube 31, it being entirely practicable with the employment of the means above described for controlling the light within the chamber-casing 64 to employ a stationary prism 48 or a stationary angularly-placed mirror in lieu of such prism. I deem it to be of very great importance to dispense with the well-known vibratory and oscillatory retinoscopic mirror and to employ in lieu thereof the prism 48 or a stationary angularly-placed mirror, since by reason thereof the instrument is rendered more satisfactory to the operator, and I believe that more satisfactory and accurate examinations may be made therewith.

At the outer end of the main casing 25 is provided the shield 27,hereinbefore described, and below this shield is provided the chinrest 80,as shown in Fig. 14, this chin-rest comprising the arm 8l, connected with a vertical slide 82, mounted upon the arm 83, extending downward from the main casing 25. The slide 82 contains the rack-teeth 84, which are engaged by the pinion-wheel 85,secured u pon the rear end of the shaft 86, said shaft 86 having at its front end the bevel gear-wheel 87 in mesh with a similar wheel 88, the latter being secured upon the shaft 89, having at its outer end the hand-wheel 90, by which the operator may, through the medium of the bevel gearwheels 87 88, effect the rotation of the shaft 86 and gear-wheel to raise and lower the slide 82 and chin-rest 80 for the purpose of adjusting the latter to suit the requirements of the patient whose eyes are to be examined. It is necessary that after the slide 82 has been adjusted to the proper position upon the depending arm 83 it may belocked in such position. Hence the shaft; 86 is capable of a limited longitudinal sliding motion, and the bracket 91, supporting the rear end of the shaft 86, is provided with the stud 92 to engage the teeth of the gear-wheel 85 when the latter is moved IOO IIC

forward, as shown in Fig. 14, for the purpose of locking said gear-wheel 85 against rotation and through said gear-wheel 85 tolock the slide 82 in rigid position. The pinion-wheel 85 will, when the shaft 8,6 is pressed rearward, pass from engagement with the stud 92,and at such time the rotation of the said gear-wheel 85 will actuate the slide 82; but when said gearwheel 85 is moved rearward to the position shown in Fig. 14 it will pass upon the stud 92 and the latter will lock said gear-wheel and the slide 82 in rigid position. The bevel gear-wheels S7 and 88, as well as the front end of the shaft 86, are mounted in a slide 93, held against the depending bracket 94 (see Figs. 14 and 15) by means of the screws 95, carried by the slide 93 and extending through a slot 9o' in the bracket 94. The slide 93 is given its sliding motion by means of the pivoted lever 97, secured to a lower arm 98 of the bracket 94 and engaging at its upper end the said slide 93. The operator by moving the lever 97 may conveniently move the slide 93 frontward or rearward to the extent permitted by the slot 96 in the bracket 94, and it is obvious that only a very limited movement of the slide 93 and shaft 8G is required. For instance, if it should be desired to lower the chin-rest from the position in which it is shown in Fig. 14 the operator by moving the lower end of the lever 97 toward the front would cause the slide 93, shaft 8G, and gearwheel to move slightly rearward, causing the gear-wheel 85 to leave the locking-stud 92, and thereupon the operator by turning the hand-wheel and bevel gear-wheels 87 and S8 will rotate the shaft 86 and gear-wheel 85 to bring the slide S2 and chin-rest 80 to the desired position. Upon the chin-rest S0 reaching the desired position the operator will cease to turn the hand-wheel 90 and will at once move the lower end of the lever 97 rearward, so as to cause the upper end of the said lever to move the slide 93, shaft 86, and gear-wheel S5 frontward, thereby causing the gear-wheel S5 to pass upon the stud 92 to enable said stud to lock said gear-wheel 85, slide 82; and chinrest 80 in rigid position.

Adjacent to the shield 27 the casing 25 is provided with the horizont-ally elongated frame 99, through which the slides 100 and 101 may be moved in a horizontal direction, the said frame 99 forming suitable slideways for the slides 100 and 101 and preferably extending beyond the sides of the casing 25 in order to a'lford support for said slides in various positions in which they may be placed during their use. The trame 99 is provided at its ends with the doors 102, which are hinged at their upper ends and are weighted at their lower portions, as shown in Fig. 2, so that said doors may close automatically. The purpose of the doors 102 is to keep the ends of the frame 99 closed to as great an extent as possible. There are two doors 102 at each end of the frame 99, and hence if only one of the lens-slides is within the frame 99 one of the doors 102 will remain closed, even though the said lens-slide within the frame 99 may project beyond the ends of the said frame 99. The doors 102 open upward, and when the lens-slide is inserted into the frame 99 the door open to admit the slide may be allowed to rest upon the upper edge of the same, as shown at the right-hand side of Fig. 2. Upon the top of the frame 99is provided a door 103, which may be opened when desired for the purpose of inspecting the lenses within the frame 99; but said door 103 must remain closed during the employment of the instrument in the examination of the eyes.

The slides 100 and 101 carry the lenses by means of which, in connection with the other parts of the instrument, the eyes may be examined. The slide 100 is simply a plain elongated slide carrying in sockets 104 spherical lenses 105, and the lower edge of the slide 100 is formed with the series of rack-teeth 106, by means of which and the gear-wheel 107, hereinafter described, the said slide 100 may be conveniently moved in a horizontal direction through the frame 99 in order to bring the appropriate lenses 105 in line with the inner tube 3l for the eye being examined. The slide 100 is shown in position within the frame 99 in Fig. 2. The slide 101 (see Figs. 5 and 6) will carry within suitable sockets 108 the cylindrical lenses 109, and said slide 101, by reason of the fact that it does carry cylindrical lenses, is provided with means for imparting the proper sliding motion to the same and also with means for axially rotating the cylindrical lenses 109. The lower edge of the slide 101 is therefore provided with rackteeth 110, corresponding exactly with the rack-teeth 106 of the slide 100, and in addition the slide 101 is provided with the rack 111, having teeth at its upper and lower edges, the teeth at its lower edge being for engagement with the pinion-wheel 107 and the teeth at its upper edge being for engagement with the toothed wheels 112, rigidly mounted upon the tubular bearings 113 of the sockets 108 for the cylindrical lenses 109, as shown in Figs. 5 and 6. While twelve slides carrying lenses will constitute the full equipment for the instrument made the subject of this application, it is suiiicient that but two of the slides (100 and 101) be illustrated, since but two of the slides will be used at any one time within the frame 99 for the slides. The full equipment of slides will comprise four slides 100, having plus spherical lenses 105, four similar slides carrying minus spherical lenses, two slides 101 carrying plus cylindrical lenses 109, and two similar slides carrying minus cylindrical lenses. I therefore illustrate in the drawings one slide 100 carrying spherical lenses and one slide 101 carrying cylindrical lenses, and these two slides 100 and 101 may be either together or singly used in connection with the other parts of the instrument hereinbefore described. The lateral sliding motion to be imparted to the slides 100 101,

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so as to bring the proper lenses within the line of the interior tube 31, will be effected by means of the pinion-Wheel 107 and shaft 114,carrying said wheel, said shaft 114 being, as hereinafter described, longitudinally movable. The pinion-Wheel 107 is utilized for moving the slides 100 and 101 and for turning the cylindrical lenses 109 axially, said pinion- Wheel being, with its shaft 114, Inova-bly arranged, so that it may be caused to engage the teeth 106 of the slide 100, or the teeth 110 of the slide 101, or the teeth of the rack 111, carried by the slide 101.

The shaft 114 at its front end carries the bevel gear-wheel 115, which is in mesh with the bevel gear-wheel 116, the latter being mounted on a shaft 117, having adjacent to the left-hand side of the casing 25 a handwheel 118, by which motion may beimparted to the gear-wheel 116 and through the latter and the gear-wheel 115 to the shaft 114 and the pinion 107, carried at the rear end thereof. In order that the shaft 114 may have a proper longitudinal motion, the front end of the shaft 114 is mounted in a slide 119, (see Fig. 11,) supported in the hanger 120, suspended from the casing 25, as shown in Fig. 7. The slide 119 may be moved by means of the pivoted lever-arm 121, secured to the hanger 120, as shown'in Figs. 7 and 11, the upper end of the said lever 121 being bifurcated, as shown in Fig. 11, to straddle a pin secured to the slide 119. The lower end of the hanger 120 is provided with a notched segment 122, and the lever 121 is provided with a spring-pressed dog 123 to engage the notches in said segment 122. By means of the lever 121 the shaft 114 may be shifted longitudinally, and by means of the springpressed dog 123, in conjunction with the segment 122, the said shaft 114 may be locked iu its adjusted positions. The object of imparting a longitudinal motion to the shaft 114 is for the purpose of causing the gearwheel 107 at the front end of the said shaft to engage either the -teeth 106 of the slide 100 or the teeth 110 of the slide 101 or the toothed racklll, carried by the slide 101, as occasion may require, the one shaft 114, with ils pinion-Wheel107, being thus adapted for both of the slides 100 and 101. After the pinion- Wheel 107 has been adjusted to the teeth of the slide it is intended to engage the said pinion-Wheel and shaft 114 are held in substantially rigid position by means of the spriugpressed dog 123 and segment 122. Ordinarily the slide 100, carrying the spherical lenses, will lirst be applied Within the frame 99, and this slide will be moved back and forth by the rotation of the shaft 114 and pinion-wheel107, the latter engaging the teeth 106 of said slide. Thereupon if the slide 101, carrying the cylindrical lenses 109, is required to complete the examination of the eye the said slide 101 will be inserted into thc frame 99 of the casing 25 and the pinionwheel 107 will be shifted from the slide 100 and brought into engagement with the teeth 110 of the slide 101 for the purpose of moving the latter until the proper lens 109 has been brought before the eye under examination. When it is desired to cause the cylindrical lens 109 to have an axial motion, the pinion-Wheel 107 will be shifted from the teeth 110 of the slide 101 to the teeth of the rack-bar 111, and thereupon by turning the shaft 114 and pinion-wheel 107 the cylindrical lens 109 will have an axial rotation under the direct control of the operator and while he is observing the eye under examination. Thus thel one pinion-Wheel 107 may be utilized for each of the slides carrying the lenses. Although I do not. ofcourse, limit theinvention to the use of the one pinion-Wheel 107 for these various purposes, I prefer the employment of the one pinion-wheel for the various slides in order to reduce the complexity of the instrument as a whole.

The casing 25 is provided with a smokedglass or darkened window 124, through which the patient may gaze upon some object, preferably twenty or more feet away, and thus cause his eyes to assume and remain in a natural or restful condition during their examination by the operator. The presence of the darkened window 124 will enable the patient to keep his attention directed from the light thrown on and into his eyes through the observing-tube 31, and under such conditions 'the operator will be enabled more accurately to determine the condition of the eyes and provide for their correction. The darkened window 124 is at the upper side of the casing 25 and to the front of the frame 99, through which the lens-slides are passed.

The method of employing the instrument hereinbefore described will be in large measure understood by oculists and retinoscopists from the explanations hereinbefore given; but that the subject of this application may be fully understood l Will explain the manner of using the instrument under the several conditions to be met in the eyes of patients, and, first, the patient will be seated and have the shield 27 adjusted to his face around his eyes, the light will be applied to or turned on within the chamber 64 at the outer end of the tube 63, and the patient will be directed to gaze upon some object twenty or more feet away, discernible through the smoked-glass window 124. With the telescopic tube 31 directed toward the eye of the patient and by means of the prism 48, which refr-acts the light into said eye, the operator, looking through the aperture 49 in the center of said prism, sees a luminous pinkish spot caused by the retracted or reflected light being rereflected from the pat-ients retina to the operators eye through the opening in the prism. This spot varies in size in different eyes, being from one-sixteenth of an inch to three-eighths of an inch in diameter. Within this pinkish field or luminous spot is the work of the operator confined, and it is evi- IOO IIO

dent that the larger this field is the more advantageous it will be. Hence the desirability of keeping the patient/s gaze fixed upon some distant object and from the retracted light from the prism 4S, for so soon as the eye looks directly at this retracted or reflected light its pupil will contract and lessen said field, and if the eye be a Very sensitive one t-he contraction will be such as to leave only a field as large as the head of a pin. Some eyes are more sensitive than others to light and some pupils are naturally larger than others, and consequently while diagnosing the operator should consider the degree of sensitiveness, together with the size of' pupil. If the eye be sensitive or the pupil small, he may shorten the telescopic tube 3l and in that way allow the rays of light more divergence, and instead of having a small concentrated beam on the eye secure a large reflection of" less penetrating power; but should the eye be such as not to be affected by this concentrated light and the pupil remain large it is better to use the tube 3l at its full length, thereby getting a sharper and more penetrative reflection and a brighter reflex. With the longer tube 3l less movement of the burner 77 is required, as it is only necessary to move the reflection (or shadow) across and off of the eye. Now that the patient is paying no attention to the light that is thrown on and into the eye the operator upon turning the light-chamber cap 69 and moving the slide 70 thereon will perceive a circular area of light move across the face; but inside the eye and within the reflex-fiek as the lighted pupil is called, is seen a shadow moving. lt is by this reflection and this shadow that the operator will diagnose and correct the eye. No matter what meridian the light is thrown across we have both the reflection and shadow, and sometimes they move with each other and sometimes against each other to a greater or less degree, according to the case. The following are examples:

First case, that of hypermetropia or far sight: The operator upon moving the burner 77 in the different meridians will note that the shadow in the eye moves with the reflec tion on the face in each meridian, seeing no streak, buta clear even surface of either pinkish, reddish, or perhaps bluish hue, and without regard to color, but from the movements of reflection and shadow, he will know that the case in hand is one of hypermetropia. This defect is corrected with convex spherical lenses, and so from the set of lens-slides the operator will take the one containing the needed convex lenses and move the same through the frame 99, first bringing the weak est lens before the eye, and continue moving the burner 77. It the reflection and shadow still correspond in movement, the operator will move in succession the stronger lenses before the eye until he finds the one that Will make the shadow move against or in an opposite direction to the reflection. This over corrects the defect and makes the eye temporarily myopie or near-sighted, and then the operator will understand that he is to drop back to the next weaker lens, which still allows the correspondence of movements, and prescribe that as the one to be worn.

Second case, that of myopie or near sight: In this second case instead of' the movements of reflection and shadow being with cach other they move against or opposite to one anot-herin every meridian. To correct myopia concave spherical lenses are used, and hence the proper lens-slide will be moved into the frame 99, and the operator will find the weakest lens that will make the movements of reflection and shadow correspond, and prescribe the same. l

Third case, that of simple hypermetropic astigmatism, axis ninety degrees: Upon looking at this eye the operator will note a streak running vertically across it of a lighter hue than the rest, and the' movements of reflection and shadow will correspond, so far as going with each other is concerned; but while the vertical meridian is perfect, the meridian at right angles or horizont-al needs correction. If' the operator now uses the strong spherical lens, although he will correct the horizontal he will over-correct the vert-ical meridian. Consequently spherical lenses cannot be used to correct this case and cylindrical lenses must be resorted to. The cylindrical lens or cylinder, as it is commonly called, is one which has one surface usually plane, while the other is a segment of a cylinder. lf a convex cylinder be held vertically, the vertical meridian will be plane, exercising no influence on the rays of light passingthrough it on that meridian, while the horizont-al meridian will be convex and act as such on rays passing through it. The plane meridian (in this case the vertical) is called the axis of the lens. By placing such lenses before the eye with the axis over the streak, which is the perfect meridian, the operator can, with the lens of proper strength, correct the horizontal meridian and still not change the vertical or perfect meridian.

Fourth case, that ot simple myopie astigmatism: This would be treated in the same way as case three, but with the use of con cave instead of convex cylinders. In astigmatism each principal meridian is treated as a case of' hypermetropia or myopia.

Fifth case, that of compound hyperopic astigmatism: In this case we still have the streak, but there is hypermetropia as well as hyperopic astigmatism, and so the operator will take the convex-spherical-lens slide and move it across until he corrects the meridian coinciding with the streak, thus reducing the case to simple hyperopic astigmatism, whereupon the operator will proceed as in case three, with convex cylinders with the axis in line with said streak.

Sixth case, that of compound myopie astig- IOO IIO

ISO

matism: Same method as in case five to be followed except that concave spherical lens is first used and then a cylinder.

Seventh case, that of mixed astigmatism: This is where the movements of reflection and shadow correspond in one meridian and go against each other in the meridian at right angles. Start with convex spherical lenses and correct the meridian that is hyperopic,

(While doing` this the other principal meridian.

is made Worse,) and having the hyperopic meridian fully corrected then use the concave cylinders and correct t-he myopie astigmatism that still exists in same manner as explained above for the correction of a case of simple myopic astigmatism.

The method of employing the instrument made the subject hereof having been thus fully described, it will be understood that the operator from his own observations determines and corrects the eyes of the patient, the patient not being called upon to state how the various lenses appear to inuence his eyesight.

While I consider the employment of the prism 48 as of great advantage for directing the rays ot' light through the observing-tube S1 to the eyes of t-he patient, I do not in every instance limit the invention to the employment of the prism, since, as shown in Fig. 18, a mirror 200, having an aperture 201, may be introduced into the chamber 47 of the casting 50 as a substitute forthe prism 48. The mirror 200 is placed at the proper angle to reliect the light thro ugh the observin g-tu be 3l to the eyes of the patient and remains in rigid position. It is one important feature of a part of the present invention that the prism 48 or the mirror 200, if the latter be used, may remain in stationary position and not required to be oscillated and tilted or vibrated in the manner required in the employment of retinoscopes of the character heretofore produced. The vibrating or tilting of the mirrors of retinoscopes heretofore produced varies and obstructs the vision of the operator through the aperture in the mirror, and this does not occur with the use ot the stationary prism 48 or the stationary mirror 200. The light in the chamber 64 may, as hereinbefore described, during the examination ot the eyes of the patient be moved along the various meridians by means of the slide 70, carrying the light-bracket 76 and the rotary cap 69, upon which the rack is mounted, and for the purpose of determining the various positions to which the rotary cap 69 and slide 70 will be moved I provide the graduated scale 202 on the light-chamber 64 and secure upon the cap 69 the pointer 203, which pointer during the partial rotary movement of the cap 69 will travel along said scale 202. The lightchamber 64 is preferably stationary; but the burner therein is movable. While a portion of the present invention is limited to the stationary prism 48 or stationary mirror 200, the entire apparatus is not limited to the employment ot' a stationary prisml or a stationary mirror, since all those parts of the apparatus or instrument pertaining to the casing 25, movable telescopic tube 3l, dark window 124, and the several features connected with the outer portion of the instrument are capable of use with the rotary and vibratory retinoscopic mirror and in themselves constitute important advances in the art, Whether employed in connection with a stationary prism or mirro r ora rotary and vibratory or tilting mirror.

The invention is not limited in every instance to the employment of a stationary prism 48, since very benecial results over the prior art may be attained by the use of the prism 48, Whether the latter is mounted in a rigid frame or a movable frame.

What I claim as my invention, and desire to secure by Letters Patent, is-

l. In an instrument for the examination of the eyes, the exterior casing forming a dark chamber and having at its outer end the eyeopening, and the movable observing tube Within and less in diameter than said casing and having at the operators end the light-directing means, combined with the light-tube leading to said observing-tube and through which the rays of light pass to said light-direct-ing means, the said casing being provided with means for the reception of the lens or lenses intermediate the outer end of said movable tube and the aforesaid opening; substantially as set forth.

2. In an instrument for the examination of the eyes, the exterior casing forming a dark chamber and having an eye-opening at its outer end, the darkened window provided in said casing, and means for the reception of the lens or lenses intermediate said Window and said opening, combined with the observing-tube within said casi ng and having at the operators end the apertured light-directing means, and means for creating artificial light for transmission by said light-directing means to the said eye-opening; substantially as set forth.

In an instrument for the examination of the eyes, the exterior casing forming a dark chamber and having an eye-opening at its outer end, the darkened Window provided in said casing, and means for the recept-ion of the lens or lenses intermediate said Window and said opening, combined with the pivoted observing-tube within said casing and having at the operators end the apertured light-directing means, means for moving said tube from in line with one eye to in line with the other eye of the patient, a guard at said eyeopening to shield both eyes of the patient, and means for creating artificial light for transmission by said light-directing means to the said eye-opening; substantially as set forth.

4. In auinstrument for the examination of the eyes, the lens-slides having the rack-teeth and adapted for passage across the eye-opening of the instrument, combined with the pin- IOO IIO

IIS

ion-Wheel for engaging the teeth of either of said slides, the longitudinally-movable shaft carrying said pinion-Wheel, means for shifting said shaft longitudinally so that said pinion-wheel may be caused to engage the rack of the slide it is desired to move, and means for then rotating said shaft to eifect the movcment of the slide; substantially as set forth.

5. In an instrument for the examination of the eyes, the exterior casing forming a dark chamber and having at its outer end the eyeopening, and the movable telescopic observing-tube Within and less in diameter than said casing and having at the operators end the lightdirecting means, combined with the light-tube leading to said observing-tube and through which the rays of light pass to said light-directing means, the said casing being provided with means for the reception of the lens or lenses intermediate the outer end of said movable tube and the aforesaid opening; substantially as set forth.

6. In an instrument for the examination of the eyes, the exterior casing forming a dark chamber and having at its outer end the eye opening, the transverse frame in said easing adjacent to said opening to receive and guide the lens-carrying slides, the doors at the ends of said frame to close the openings thereof and hinged at their upper ends so that they may close automatically, and the elongated slides carrying the lenses and adapted to said frame, combined with the observingtube Within said casing and having at the operators end the light-directing means; substantially as set forth.

7. In an' instrument for the examination of the eyes, the observing-tube having at the opcrators end means, containing the observation-aperture, for directing the rays of light through said tube, and means for creating the light for transmission by said light-directing means, combined with the casing forming a dark chamber and inclosing the outer end portion of said tube, said casing having an eye-opening at its outer end and being provided with means for the reception of the lens or lenses intermediate the outer end of said tube and said eye-opening; substantially as set forth.

8. In an instrument for the examination of the eyes, the observing-tube having at the operators end means, containing the observation-aperture, for directing the rays of light through said tube, and means for creating the light for transmission by said light-directing means, combined with the casing forming a dark chamber and inclosing the outer end portion of said tube, said casing having an eye-opening at its outer end, the dark Window through which the patients eye may look at a distant object, and means for the reception of the lens or lenses inline with said eye-opening; substantially as set forth.

9. In an instrument for the examination of the eyes, the observing-tube, and the stationary means, containing the observation-aperture, for directing the rays of light through said tube to the eye under examination, combined with movable light-supply means for cooperation with said light-directing means; substantially as set forth 10. In an instrument for the examination of the eyes, the observing-tube, and means at the operators end of said tube for directing the rays of light through said tube ro the eye under examination, said means having the observation-aperture and being rigidly secured in its alined relation to said observing-tube so that said aperture remains in constant alinement with said tube, combined with movable light-supply means for coperation with said light-directing means; substantially as set forth. i

11. In an instrument for the examination of the eyes, the observing-tube, and the prism at the operators end of said tube for directing the rays of light through said tube to the eye under examination, said prism having the observation-aperture, combined with lightsupply means for cooperation With said prism; substantially as set forth.

12. In an instrument for the examination of the eyes, the observing-tube, a guard for the eyes in line with the outer end of the said tube, the means at the other end of said tube for directing the rays of light through said observing-tube to the eyes to be examined, and means for creating artificial light to be transmitted by said light-directing means through said tube, said light-directing means having the observation-aperture therein, combined with the chin-rest 80 below said guard, the vertical frame supporting said chin-rest and having the rack-teeth 841, the pinion-wheel S5 to engage said rack-teeth, the shaft 86 carrying said gear-Wheel and being longitudinally movable, means for rotating said shaft, means for shifting said shaft, and the rigid stud 92 to engage said gear-Wheel for locking the same and said chinrest in stationary position; substantially as set forth.

13. In an instrument for the examination of the eyes, the observing-tube, means at the operators end of said tube for directing the rays of artificial light through said tube, and having the observation-aperture, the main frame supporting said observing-tube and having at its outer end, beyond the outer end of said observing-tube, the frame to receive IOS IIO

the lens-slide and also having the guard for ofthe eyes, the observing-tube, and the means, containing the observation-aperture, for directing the rays of .light through said tube to the eye under examination, combined with the ligl1t-eham ber easing connected with said observing-tube, means within said easing for supplyingartieial light, and means for shifting on the Various meridians said light-supplying means; substantially as set forth.

l5. In an instrument for the examination of the eyes, the observing-tube, and the means, containing the observation-aperture, for directing the rays of light through said tube to the eye under examination, combined with the light-chamber easing connected With said observing tube, means for supplying the light mounted within said easing, the slide connected with said light-supplying means and adapted to be shifted for moving said means, and the rotary eap carrying said slide and adapted to be rotated therewith; substantially as set forth.

16. In au instrument for the examination of the eyes, a suitable support, and the prism containing the observation-aperture for direeting the rays of light to the eye under examination, combined with movable ligh t-supply means for ooperation with said lightdirecting means, as set forth.

Signed at New York eity, in the county of New York and State of New York, this 15th day of September, A. D. 1900.

ELMER LE ROY RYER.

Witnesses: l

CHAS. C. GILL, GUNDER GUNDERSON. 

